Complex from a polyvalent metal petroleum sulfonate, a process of making it, and a lubricating oil containing it



Patented Apr. 12, 1949 COIVIILEX FROM A POLYVALEN'I METAL PETROLEUM SULFONATE. A PROCESS OF MAKING IT, AND A LUBRICATING OIL CONTAINING I'I Gordon W. Duncan. Westfield, and John C. Zimmer, U

nion, N. 1., assignors to Standard Oil Development Company, a corporation of Delaware No Drawing. Application January 6, 1945, Serial No. 571,664

21 Claims. (Cl. 252-33) 1 This invention relates to compounded mineral lubricating oils and more particularly deals with lubricating oils containing oil-soluble sulfonates of polyvalent metals, which oils are substantially non-corrosive and possess the property of preventing sticking of piston rings in internal combustion engines when running these engine for long periods of time under severe operating conditions. It is known that in modern Diesel engines and aviation gasoline engines, as well as in ordinary automotive engines, operating with high power output and at relatively high temperatures, piston rings have a tendency to become stuck in their grooves. Accumulation of lacquer and/or carbonaceous deposits on the rings and grooves appears to be the most probable reason for this occurrence. The addition of certain types of metal derivatives of organic compounds is known to improve the properties of these oils, such as their o iliness characteristics and their detergent action in engines, particularly manifested in the maintenance oi. a clean engine condition during operation. Various metal compounds which have been used for such purposes include the metal derivatives of such organic compounds as fatty acids, naphthenic acids, alcohols, phenols, ketones, and the like.

It is also known that calcium and other metal salts of petroleum or other sulfonic acids have been used as engine oil detergent addition agents. These materials are effective to a moderate degree but their plastic nature poor oil-solubility, and corrosive tendencies make their use diiiicult.

It is an object of the present invention to provide a new class of addition agents for oils which are to be used as crankcase lubricants for internal combustion engines and which exhibit to a high degree the desirable properties of promoting general engine cleanliness, and reducing ring stickin piston skirt varnish formation and the like.

It is a still further object of this invention to prepare lubricating oils, for such severe service conditions as are encountered in high speed Diesel engines, which oils possess detergent properties and thereby avoid deposition or lacquer,

asphaltenes and varnish-like materials on the pistons, behind the rings and in the ring grooves.

According to the present invention these and other objects are attained by adding small amounts, in the order of about 0.1% to 5.0%, of an oil-soluble complex metal salt of a sulfonic acid. Particularly suitable sulfonate salts for this purpose are those of the alkaline earth metals, e. g. calcium, magnesium, strontium and barium. However, complexes of other metal sulfonates may 2. be used, such as those of aluminum, iron, tin, zinc, cadmium, lithium cobalt, nickel etc.

The petroleum sulfonates which are of major current interest are the soaps of oil-soluble or so-called mahogany acids, which are usually produced during treatment of lubricating oil distillates, or of rafllnates or extracts thereof, with concentrated to fuming sulfuric acid, and remain in the oil after settling out the sludge. These sulfonic acids may be represented as where (R) is one or more alkyl, alkaryl or aralkyl groups and the aromatic nucleus may be a single or'condensed ring or a partially hydrogenated ring. The lower molecular weight acids can be .extracted from the acid-treated oil by adding a small amount or water, preferably after dilution of the oil with kerosene. However, the more desirable high molecular weight (350 to 500) acids, particularly those produced when treating for white oil with fuming acid, are normally recovered as sodium soaps by neutralizing the acid oil with sodium hydroxide or carbonate and extracting with aqueous alcohol. The crude soap extract is first recovered as a water curd after removal of alcohol by distillation and a gravity separation of some of the contaminating salts (e. g. sodium carbonate, sulfate and sulflte) The material still contains considerable quantities of salts and consequently is normally purified by readditlon of alcohol followed by storage to permit settling of salt brine. The alcohol and water are then stripped out and replaced with a light lubricating oil to yield the commercial purified concentrate,

' generally containing from 50% to 70% sodium sulfonate.

To prepare polyvalent metal sulfonates, acid treated oils or extracted sulfonic acids may be neutralized directly with an oxide, hydroxide or carbonate of the desired metal. However, it is often more convenient-to prepare them from the sodium salts by double decomposition. Thus, the polyvalent metal salts may be made by precipitating the sodium sulfonates from alcoholic solution with a polyvalent metal salt, or an oil solution of sodium sulfonates may be emulsified with an aqueous solution of the polyvalent metal salt. For example, the calcium metal sulfonates may 'be prepared by precipitating from alcohol solution with calcium chloride, inorganic salts then being removed by washing with water and by filtration.

centrate is given in the following table:

TABLE I Calcium sulfonate percent 26.0 Sodium sulfonate do 1.0 Calcium content do 1.16 Sodium content do- 0.05 Sulfur content do 2.10 Chlorine do 0.15 Neutralization value (mg. KOH/g) acid 0.54 Consistency Solid The data in the above table indicate that these sulfonates are substantially normal calcium sulfonates having a stoichiometric ratio of calcium to sulfonic acid. These normal calcium sulfonates, however, exhibit only fair engine detergency and are poorly oil-soluble.

It has now been found that normal polyvalent metal sulfonates tend to form complexes with other salts particularly with inorganic salts, when such salts are present with the sulfonate during the dehydration step. Such complexes, or coordination compounds, are not formed in the manufacture of polyvalent metal sulfonates inasmuch as the inorganic salts are removed by water washing before the sulfonates are dehydrated in the presence of oil as described above. Furthermore, it is necessary that the dehydration be carried substantially to completion in order to form the complex sulfonates.

In co-pending application, Ser. 564,546, filed November 21, 1944, it has been shown that when converting a sodium sulfonate to a polyvalent metal derivative by the methods outlined above, if some of the inorganic salt employed for the conversion is allowed to'remain during the final dehydration step, a portion of the excess salt forms a complex, or coordination compound, with the sulfonate. This complex, being oil-soluble, remains in solution during filtration of the final oil blend. Such sulfonate coordination compounds have been found to be superior to the normal sulfonates as detergent additives for crankcase lubricants and are also more satisfactoryfrom the standpoint of oil solubility. The improvement in oil solubility is readily noted during the manufacture of the coordination compounds. A 25 to 30% concentrate of a normal sulfonate of a polyvalent metal-in oil will be very viscous and often gel-like in nature but when the sulfonate is converted to a coordination compound the concentrate will be found to be quite fluid. Thus, it may be said that the process of the invention serves to "fluidize the sulfonates.

According to the present invention, coordination compounds are prepared by adding a nitrogen-base salt to the polyvalent metal sulfonate in addition to or in place of the inorganic salt remaining from the conversion of the sodium sulfonate to a polyvalent metal salt. For example, if sodium sulfonate has been converted to calcium sulfonate, excess calcium chloride may be allowed to remain, and then before dehydration ammonium chloride may also be added. Or, if a diiferent type of coordination compound is to be formed, the excess calcium chloride from the conversion step may be removed by water washing or by other suitable means, and other materials such as ammonium nitrate or ammonium chloride may be added before the dehydration step. sulfonates prepared by direct neutralization of sulfonic acids may be similarly converted to coordination compounds by emulsifying concentrated or dilute oil solutions of the sulfonates with aqueous solutions or suspensions of the nitrogen-base salt followed by dehydration in the manner already described. Suitable nitrogen-base salts include various ammonium salts and quaternary ammonium salts. Certain organic nitrogen bases may also be used such as aniline, aniline hydrochloride, cyclohexylamine, quinoline, lauryl amine, oleyl amine, diethylamino ethanol and similar compounds. In general, it is preferable that these nitrogen base compounds have boiling points higher than 250 F.

When preparing coordination compounds by the methods of the present invention care must be taken not to select salts which will react with the sulfonate to form water-insoluble salts of the polyvalent metal already combined with the sulfonic acids. Thus, for example, ammonium sulfate should not be chosen to make a coordination compound with calcium sulfonates because by double decomposition ammonium sulfonate and calcium sulfate would be formed instead of the desired complex sulfonate.

The materials listed below have been-found to be effective to a greater or less degree in fluidizing, that is, reducing materially the consistency of a solid 30 concentrate of normal calcium sulfonates in oil. The metal sulfonates listed in TABLE II Fluid- Amount Compound Used izmg Used Effect 4 Per cent 1 Ammonium nitrate 3.3 Good. 2 Ammonium chloride 3.3 Do. 3 Oleyl Amine 3.3 Fair. 4 Diethyl amino ethanol 6.7 Do.

1 Based on weight of sulfonate.

The structure of the complexes formed by the processes of the present invention is not fully understood but it is believed that they are in the nature of Werner coordination compounds. Although sulfonates are known to be powerful occluding agents, the fact that oil concentrates of calcium sulfonates containing excess metal or other salts or bases are extremely fluid, while the oil concentrates of the normal sulfonates are gelatinous in nature, indicates that the added nitrogen base compounds are present as weak or secondary addition products or possibly as double salts, rather than as occluded material. It would seem that the occlusion of inorganic salts would not contribute to oil-solubility. Inorganic compounds cannot be introduced intov normal metal sulfonate concentrates except in the presence of an appreciable amount of water, indicating that ionization is a factor in the formation of some of the coordination compounds. Neither chloride nor hydroxyl ions can be detected in water which has been agitated several minutes at room temmore than the theoretical amount 01' metal. It

is possible that they may be represented by the following formula, using the calcium sulionateammonium chloride complex as an example.

' a). so.- Ca :Nmci

where (12).. represents one or more alkyl or aralkyl groups.

In the above formula the colon indicates that the calcium contributes both electrons to form a Werner coordination compound. It should be understood that the above structural formula is merely one which has been postulated on the.

fonating alkyl aromatic hydrocarbons, such as.

alkyl benzenes, alkyl naphthalenes, alkyl anthracene, alkyl phenanthrenes, alkyl picenes, alkyl chrysenes, alkyl biphenyls, etc., provided the number of carbon atoms in the alkyl chain or chains is suflicient to render the resulting sulfonic acids and their salts soluble in hydrocarbon .oil. It is desirable that at least one alkyl radical be relatively long, i. e., contain at least 8 or more carbon atoms, not only because of solubility in hydrocarbon oils, but also for the reason that long alkyl chains improve the anti-ringsticking efficiency of the salts formed with the sulfonic acids. Thus, an aromatic hydrocarbon suitable for the production of highly eflicient sulfonic acids may be produced by condensation of aromatic hydrocarbons with chlorinated paraflin naphthene sulionic acids, terpene sulfonic acids, etc., are also suitable.

When preparing finished lubricating oils according to the present invention, the sulfonate complexes or their concentrates are stirred into a suitable mineral lubricating oil base stock and the solution is effected by agitation, heating being employed, if desired, to facilitate the operation.

Generally, the addition agents or the present invention are most advantageously blended with lubricating 011 base stocks in concentrations between the approximate limits of 0.02% and 5.0% and preferably from 0.1% to 2.5%, although larger amounts may be used for some purposes. The exact amount of addition agent required for a maximum improvement depends to a certain extent on the particular products used, the nature of the lubricating oil base stock and the general operating conditions of the engine in which the lubricant is to be employed.

As has been pointed out elsewhere in this speci fication, it is often convenient to prepare concentrates of the additives in oil, containing, say, to 75% of effective addition agent, the concentrate later being added to a, suitable lubricating oil base stock to give a finished blend containing the desired'percentage of additive. Thus, when using a concentrate, 4.3% of this material maybe blended with a suitable base stock to give a finished oil containing 1.5% of etl'ective addition agent.

In the following examples are described preparations of products in accordance with this in- I stood that these examples, given for illustrative wax, alkyl chlorides such as octyl, decyl, cetyl,

etc., chlorides, fatty alcohols, long chain olefins such as may be obtained in the cracking of wax, etc. Suitable condensing agents may be employed, such as Friedel-Crafts catalysts, sulfuric acid, phosphorus pentoxide, phosphoric acid, etc.

The hydrocarbon sulfonic acids may, if desired, contain substituent radicals such as hydroxyl, primary, secondary or tertiary amine, ether, sulfide, hydrosulfide, disulfide, halogen, etc., radicals which may be attached to thering or to side chains or both. For example, paramn wax substituted naphthalene mono sulfonic acids, which contain a sulfonic radical attached to one ring of the naphthalene nucleus and a hydroxyl or amino radical attached to the other ring, may be employed.

Phenol sulfonic acids such as isohexadecyl phenol sulfonic acid, wax phenol sulfonic acid, and the like, as well as olefin sulfonic acids,

purposes only, are not to be construed as limiting the scope of the invention in any way.

Example I A solution of sodium sulfonates was prepared by extracting with aqueous alcohol a sodium carbonate neutralized, sulfuric acid-treated phenol rafiinate of a naphthenic distillate oil, the original oil having a Saybolt viscosity of 800 seconds at 100 F. The extract was steam distilled to remove alcohol and most of the water and then reagitated with more concentrated aqueous alcohol and stored to separate insoluble salts. The

alcohol solution was mixed with oil and heated" to drive off the alcohol. The concentration oi. sodium sulfonates was then adjusted with sufficient oil to give a 30% concentrate, and emulsified with an excess of an aqueous calcium chloride solution. The emulsion was then agitatedand heated to a temperature between 230 and 255 F., whereupon most of the sodium chloride separated and was drawn off. The excess calcium chloride was removed by washing. 1500 grams of this concentrate was emulsified with grams of water containing 15 grams of ammonium chloride, and heated with stirring to 310 F. to efiect dehydration. The product was then filtered, giving a fluid concentrate of a calcium sulfonate-ammonium chloride complex. Whereas the original calcium sulfonate concentrate was a 'very viscous gel-like product having a Saybolt viscosity at 210 F. of about 10560 seconds and a pour point of about 150 F., the calcium sulfonate-ammonium chloride concentrate obtained by the above procedure was quite fluid, having a Saybolt viscosity at 210 F. of 370 seconds and a pour point of about 50 F.

Example 11 The coordination compound of Example I and a normal calcium petroleum sulfonate were each blended in an SAE 10 grade, solvent extracted naphthenic base lubricating oil and submitted to bearing corrosion tests.

The bearing corrosion tests were conducted as follows: 500 cc. of oil to be tested was placed in a glass oxidation tube (13" long and 2%" diameter) fitted at the bottom with a /4" bore air inlet tube perforated to facilitate air distribution. The oxidation tube was then immersed in a heated bath so that the oil temperaturetwas maintained at 325 F. during the test. Two quarter sections of automotive bearings of copper-lead alloy of known weight having a total area of 25 sq. cm. were attached to opposite sides of a stainless steel rod which was then immersed in the oil and rotated at 600 R. P. M., thus providing sufficient agitation of the sample during the test. Air was then blown through the oil at the rate of 2 cu. ft. per hour. To increase the severity of the test, the bearings were washed and weighed after 4 hours and then polished and reweighed before continuing for another four hour period. The results show the cumulative weight loss at the end of four and eight hours.

The results of the bearing corrosion tests are given in the following table. In each case the oil blend contained 1.5% of metal sulfonate (about 5% of the oil concentrate). It will be seen from'the results of these tests that the sulfonate coordination compound was considerably less corrosive than the original normal calcium sulfonate.

TABLE III {Bearing corrosion tests] Although in most instances the addition agents of the present invention will of themselves impart sufficient improvement to lubricating oils to give very satisfactory results, still greater improvement may often be obtained by employing these addition agents in conjunction with other agents of the detergent type-such as metal soaps, metal phenates, metal alcoholates, metal phenol sulfides, metal organo phosphates, thiophosphates, phosphites and thiophosphites, metal sulfonates, metal thiocarbamates, metal xanthates and thicxanthates, and the like.

Thus the addition agents of our invention may be used in mineral lubricating oils in conjunction with one or more of the following representative materials:

Barium tert.-octyl phenol sulfide Cobalt tert.-amyl phenol sulfide Tin salt of wax alkylated phenol sulfide Magnesium cetyl phenate Nickel oleate Calcium dichlorostearate Aluminum-calcium mixed soap of fatty acids from oxidation of petroleum fractions Calcium isohexadecyl phenol sulfonate Barium octadecylate Calcium phenyl atearate Nickel dibutyl dithiocarbamate Nickel amyl xanthate Zinc salt of salicylic acid sulfide octyl ester Barium salt of bis (2,4-diamylphenol) -4-amylphenol dithioethcr Reaction product of calcium tert. octyl phenol sulfide and sulfur Reaction product of barium tert. octyl phenate and phosphorus pentasulflde Barium dioctyl dithiophosphate Zinc methyl cyclohexyl dithiophosphate Calcium dihexadecyl monothiophosphite Calcium cetyl phosphate Zinc diisopropyl salicylate Tin naphthenate Aluminum naphthenate Calcium double salt of octadecyl phenol sulfonic acid Barium phenate-zinc sulfonate of isohexadecyl phenol sulfonic acid Barium di-tert.-amyl phenol sulfide Calcium phenate-barium carboxylate of octadecyl salicylic acid Barium 2-stearoyl-4-amyl phenol sulfide Zinc lauryl mercaptide The lubricating oil base stocks used in the compositions of this invention may be straight mineral lubricating oils or distillates derived from paramnic, naphthenic, asphaltic or mixed base crudes, or if desired, various blended oils may be employed as well as residuals, particularly those from which asphaltic constitutents have been carefully removed. The oils may be refined by conventional methods using acid, alkali and/or clay or other agents such as aluminum chloride, or they may be extracted oils produced for example by solvent extraction with solvents of the type of phenol, sulfur dioxide, furfural, dichloro ethyl ether, nitrobenzene, crotonaldehyde, etc. Hydrogenated oils or white oils may be employed as well as synthetic oils prepared, for example,

5 by the polymerization of olefins or by the reaction of oxides of carbon with hydrogen or by the hydrogenation of coal or its products. In certain instances cracking coiltar fractions and coal tar or shale oil distiliates may also be used. Also for special applications various organic esters or animal, vegetable or fish oils or their hydrogenated, polymerized or voltolized products may be employed, either alone or in admixture with mineral oils.

For the best results the base stock chosen should normally be that oil which without the new addition agents present gives the optimum performance in the service contemplated. However, since one advantage of the agents is that their use also makes feasible the employment of less satisfactory mineral oils or other oils, no strict rule can be laid down for the choice of the base stock. Certain essentials must of course be observed. The oil must possess the viscosity and volatility characteristics known to be required for the service contemplated. The oil must be a satisfactory solvent for the addition agent, although in some cases auxiliary solvent agents may be used. The lubricating oils, however they may have been produced, may vary considerably in viscosity and other properties depending upon the particular use for which they are desired, but they usually range from about 40 to seconds Saybolt viscosity at 210 F. For the lubrication of certain low and medium speed Diesel engines the general practice has often been to use a lubricating oil base stock prepared from naphthenic or aromatic crudes and having a Saybolt viscosity at 210 F. of 45 to 90 seconds and a viscosity index of to 50. However, in certain types of Diesel service, particularly with high speed Diesel engines, and in aviation engine and other gasoline engine service, oils of higher viscosity index oiliness agents, resins, rubber, olefin polymers, 7

voltolized fats, voltolized mineral oils, and/or voltolized waxes and colloidal solids such as graphite or zinc oxide, etc. Specific examples of such other compounds include dibenzyl disulfide, sulfurized sperm oil, voltolized sperm oil, phenyl alpha naphthylamine, pclyisobutylene, polymerized lauryl methacrylate, diamyl trisulfide, sulfurized wax olefins, tricresyl phosphate, 2, 6-ditert. buty1-4-methyl phenol, and the reaction product of phenol with sulfur chloride treated diisobutylene. Solvents and assisting agents, such as esters, ketones, alcohols, thioalcohols, amines, aldehydes, halogenated or nitrated compounds, and the like, may also be employed.

Assisting agents which are particularly desirable are the higher alcohols having eight or more carbon atoms and preferably 12 to carbon atoms. The alcohols may be saturated straight and branched chain aliphatic alcohols such as octyl alcohol (CaHnOH), lauryl alcohol (C12H25OH), cetyl alcohol (CmHsaOH), stearyl alcohol, sometimes referred to as octadecyl alcohol, (CmHavOH), heptadecyl alcohol (CrzHasQH), and the like; the corresponding olefinic alcohols such as oleyl alcohol, arylic alcohols, such as naphthenic alcohols; and aryl substituted alkyl alcohols, for instance, phenyl octyl alcohol, or octadecyl benzyl alcohol or mixtures of these various alcohols, which may be pure or substantially pure synthetic alcohols. Certain mixed naturally occurring alcohols such as those found in wool fat (which is known to contain a substantial percentage of alcohols having about 16 to 18 carbon atoms) and in sperm oil (which contains a high percentage of cetyl alcohol) may be used. Although it is preferable to isolate the alcohols from those materials, for some purposes the wool fat, sperm oil or other natural products rich in alcohols may be used per se. Products prepared synthetically by chemical processes may also be used such as alcohols prepared by the oxidation of petroleum hydrocarbons, e. g., parafi'in wax, petrolatum, etc. Other assisting agents include stearyl nitrile and stearyl amine.

These assisting agents serve to enhance the detergent and sludge dispersive qualities and aid the solubility of the metal-containing addition agents and at the sametime impart some oiliness properties to the lubricating oil compositions.

Although the present invention has been described with a certain degree of particularity, it is to be understood that the present disclosure has been made only by way of example and that numerous changes in the details and other features of the invention may be resorted to without departing from the spirit and scope of the invention as hereinafter claimed.

The nature and objects of the present invention 10 having thus been setqiorth and a specific illustration of the same @en, What is claimed as new and useful and desired to be secured by Letters Patent is:

1. A lubricating oil containing 0.1 to 2.5% of the complex formed from calcium petroleum sulfonate and ammonium chloride.

2. A method for preparing polyvalent metal hydrocarbon sulfonates comprising treating mineral lubricating oil with concentratedto fuming sulfuric acid, neutralizing the acid-treated oil with a basic alkali metal compound, extracting the neutralized oil with alcohol, precipitating the polyvalent metal sulfonate by adding a watersoluble polyvalent metal salt of an acid the said polyvalent metal salt of which is soluble in water and dehydrating the polyvalent metal sulfonate in the presence of an ammonium salt selected from the class consisting of ammonium chloride and ammonium nitrate.

3. A method for preparing a concentrate of a polyvalent metal hydrocarbon sulfonate complex comprising treating a mineral oil with concentrated to fuming sulfuric acid, neutralizing the acid oil with a polyvalent metal hydroxide, emulsifying the oil solution of polyvalent metal sulfonate with an aqueous solution of an ammonium salt, selected from the group consisting of ammonium chloride and ammonium nitrate, the said polyvalent metal salt of which is soluble in water, heating the product to remove water, and filtering the dehydrated product.

4. A method for preparing a concentrate of a polyvalent metal hydrocarbon sulfonate complex comprising treating a mineral lubricating oil with concentrated to fuming sulfuric acid, neutralizing the acid-treated oil with a basic alkali metal compound, extracting the neutralized oil with alcohol, precipitating the polyvalent metal sulfonate with a polyvalent metal salt, and dehydrating the precipitated polyvalent metal sulfonate in the presence of oil and an ammonium salt, selected from the group consisting of ammonium chloride and ammonium nitrate, the said polyvalent metal salt of which is watersoluble.v

5. A method for preparing calcium hydrocarbon sulfonate complexes comprising treating lubricating oil with concentrated to fuming sulfuric acid, neutralizing the acid-treated oil with sodium carbonate, extracting the neutralized oil with alcohol, precipitating calcium sulfonate by adding to the alcohol extract a water-soluble calcium compound, and dehydrating the precipitated calcium sulfonate in the presence of an ammonium salt of an acid whose calcium salt is soluble in water, said ammonium salt being selected from the group consisting of ammonium chloride and ammonium nitrate.

6. A method for preparing calcium hydrocarbon sulfonate complexes comprising treating minerallubricating oil with concentrated to fuming sulfuric acid, neutralizing the acid-treated oil with sodium carbonate, extracting the neutralized oil with alcohol, precipitating the calcium sulfonate by adding calcium chloride to the alcohol extract, and dehydrating the calcium sulfonate in the presence of an ammonium salt of an acid whose calcium salt is water-soluble, said ammonium salt being selected from the group consistingof ammonium chloride and ammonium nitrate.

'7. A method for preparing a concentrate of a calcium hydrocarbon sulfonate complex comprising treating mlneral lubricating oil with concentrated to fuming sulfuric acid, neutralizing nium chloride solution, and heating the mixture to 310 F. to remove water and filtering.

8. A method for preparing a concentrate of a calcium hydrocarbon sulfonate complex comprising treating mineral lubricating oil with concentrated to fuming sulfuric acid, neutralizing the acid-treated oil with sodium carbonate, extracting the neutralized oil with alcohol, separating the alcohol from the extract of sodium sulfonates, dissolving the sodium sulfonates in-oil, emulsifying the solution of sodium sulfonates in oil with an excess of 1% calcium chloride solution, washing free of chlorides, adding ammonium chloride, heating to 310 F. to remove water and filtering.

9. A method for preparing a concentrate of a calcium hydrocarbon sulfonate complex comprising treating mineral lubricating oil with concentrated to fuming sulfuric acid, neutralizing the acid-treated oil with calcium hydroxide, filtering, distilling the oil to concentrate the oil solution, emulsifying the oil solution with aqueous ammonium chloride solution, and then heating to about 300 F. to remove water.

10. A method for preparing a concentrate of a calcium hydrocarbon sulfonate complex comprising emulsifying an oil solution of calcium sulfonate with an aqueous solution of an ammonium salt of an acid whose calcium salt is water-soluble said ammonium salt being selected from the group consisting of ammonium chloride and ammonium nitrate, heating the product to drive off water, and filtering the dehydrated product.

11. A method for preparing a concentrate of a calcium petroleum sulfonate complex comprising emulsifying an oil solution of calcium petroleum sulfonate with an aqueous solution of an ammonium 'salt of an acid whose calcium salt is water-soluble, said ammonium salt being selected from the group consisting of ammonium chloride and ammonium nitrate, heating the product to drive off water, and filtering the dehydrated product.

12. As a new composition ofmatter, the complex formed from an oil-soluble calcium petroleum sulfonate and an ammonium salt of an inorganic acid selected from the class which consists of nitric and hydrochloric acids.

13. As a new composition of matter, the complex formed from an oil-soluble calcium petroleum sulfonate and ammoni chloride.

14. As a new composition 0 matter, the complex formed from an oil-soluble calcium petroleum sulfonate and ammoniumnitrate.

15. A mineral lubricating oilhaving dissolved therein 0.1% to 5% of a complex compound formed between a polyvalent metal hydrocarbon sulfonate and an ammonium salt of an inorganic acid, said salt being selected from the class consisting of ammonium chloride and ammonium nitrate.

16. A mineral lubricating oil composition according to claim, 15 in which the polyvalent metal is-an alkaline earth metal.

17. A mineral lubricating oil composition according to claim 15 in which the polyvalent metal is calcium;

18. A mineral lubricating oil having dissolved therein 0.1% to 5% of a complex compound formed between an alkaline earth metal petroleum sulfonate and an ammonium salt of an inorganic acid, said salt being selected from the class consisting of ammonium chloride and ammonium nitrate.

19. A mineral lubricating oil composition according to claim 18 in which the alkaline earth metal is calcium. 1

20. As a new composition of matter, the complex formed between an oil soluble polyvalent metal petroleum sulfonate and an ammonium salt selected from the class consisting of ammonium chloride and ammonium nitrate.

-40 21. A composition of matter according to claim earth metal. GORDON w. DUNCAN.

JOH C. ZIMMER. REFERENCES CITED The following references are of record in the file of this patent:

UNITED STA'IES PATENTS Number Name Date 11,011,203 Jahn Dec. 12, 1911 2,343,841 Burk Mar. 7, 1944 2,366,743 Matuszak Jan. 9, 1945 

